bool checkAndGetDate32()

in cpp-ch/local-engine/Functions/SparkFunctionToDate.cpp [46:97]
52 lines of code
22 McCabe index (conditional complexity)

    bool checkAndGetDate32(DB::ReadBuffer & buf, DB::DataTypeDate32::FieldType &x, const DateLUTImpl & date_lut) const
    {
        auto checkNumbericASCII = [&](DB::ReadBuffer & rb, size_t start, size_t length) -> bool
        {
            for (size_t i = start; i < start + length; ++i)
            {
                if (!isNumericASCII(*(rb.position() + i)))
                    return false;
            }
            return true;
        };
        auto checkDelimiter = [&](DB::ReadBuffer & rb, size_t pos) -> bool
        {
            if (*(rb.position() + pos) != '-')
                return false;
            else
                return true;
        };
        if (!checkNumbericASCII(buf, 0, 4) 
            || !checkDelimiter(buf, 4) 
            || !checkNumbericASCII(buf, 5, 2) 
            || !checkDelimiter(buf, 7) 
            || !checkNumbericASCII(buf, 8, 2))
            return false;
        else
        {
            UInt8 month = (*(buf.position() + 5) - '0') * 10 + (*(buf.position() + 6) - '0');
            if (month <= 0 || month > 12)
                return false;
            UInt8 day = (*(buf.position() + 8) - '0') * 10 + (*(buf.position() + 9) - '0');
            if (day <= 0 || day > 31)
                return false;
            else if (day == 31 && (month == 2 || month == 4 || month == 6 || month == 9 || month == 11))
                return false;
            else if (day == 30 && month == 2)
                return false;
            else
            {
                Int16 year = (*(buf.position() + 0) - '0') * 1000 + 
                    (*(buf.position() + 1) - '0') * 100 + 
                    (*(buf.position() + 2) - '0') * 10 + 
                    (*(buf.position() + 3) - '0');
                if (day == 29 && month == 2 && year % 4 != 0)
                    return false;
                else
                {
                    x = date_lut.makeDayNum(year, month, day, -static_cast<Int32>(date_lut.getDayNumOffsetEpoch()));
                    return true;
                }
            }
        }
    }